Robospice - addListenerIfPending - 我怎么知道，如果reqest被发现？ [英] Robospice - addListenerIfPending - how do I know if reqest WAS found?

问题描述

我想实现使用robospice一个非常简单的例子：一个登录界面。当点击登录按钮，加载动画显示，并要求用做 SpiceManager.execute（..）（没有缓存，当然，因为它是一个登录请求，我需要做实际调用到服务器的每一次）。

I am trying to implement a very simple case using robospice: a login screen. When login button is clicked, loading animation is shown and request is made using SpiceManager.execute(..) (without caching, of course. Since it's a login request, I need to do actual call to the server every time).

因此​​，要处理的屏幕旋转等，在 Activity.onStart（）我应该使用 SpiceManager.addListenerIfPending（..），如果要求实际上是悬而未决，我应该显示加载动画没有做任何真正的要求。

So, to handle screen rotations, etc., in Activity.onStart() I should use SpiceManager.addListenerIfPending(..), and if request is actually pending, I should show loading animation without doing any real request.

问题是： PendingRequestListener 没有 onRequestExists（）方法。它只有 onRequestNotFound（）。

The problem is: PendingRequestListener does not have onRequestExists() method. It only has onRequestNotFound().

一个可能的（但不理想）的解决方案，就是总是吸引加载屏幕，然后调用 addListenerIfPending（..），然后删除加载动画在 onRequestNotFound（）。如果没有真正的请求，这看起来非常糟糕这就产生闪烁载入画面。什么是实现期望的行为的正确方法？

One possible (but unsatisfactory) solution, is to draw loading screen always, then call addListenerIfPending(..), and then remove loading animation in onRequestNotFound(). This creates "flickering" loading screen if there was no real request, which looks really bad. What is the proper way of implementing desired behavior?

推荐答案

好吧，如果谷歌在这里领导任何人。
妥善解决：
在现实中，这种功能是已在库中。有一个在等待处理的请求，发现其被调用的方法，它少了点什么都没有。

Ok, in case google leads anyone here. Proper solution: in reality, this functionality is already in the library. There is a method which gets called when pending request WAS found, it just does... nothing.

您需要：

1. 创建扩展自己的界面 PendingRequestListener ：

public interface MyPendingRequestListener<T> extends PendingRequestListener<T> {
    void onRequestAggregated();
}

请注意：您将需要使用的请求listeneres做通过Robospice请求时实现了这个接口

Note: you will need to use request listeneres implementing this interface when doing requests through Robospice.

创建自己的类实现 RequestListenerNotifier 。我通过复制粘贴 DefaultRequestListenerNotifier （我是不是能延长它，因为方法后（..）是这样做私营），因为它包含了其他案件porper通知执行。例如， MyRequestListenerNotifier 。

Create your own class implementing RequestListenerNotifier. I did this by copy-pasting DefaultRequestListenerNotifier (I was not able to extend it because method post(..) is private) because it contains porper notification implementation for other cases. For example, MyRequestListenerNotifier.

覆盖方法 notifyListenersOfRequestAggregated ：

@Override
public <T> void notifyListenersOfRequestAggregated(final CachedSpiceRequest<T> request, Set<RequestListener<?>> listeners) {
    post(new AggregatedRunnable(listeners), request.getRequestCacheKey());
}

private static class AggregatedRunnable implements Runnable {
    private final Set<RequestListener<?>> listeners;

    public AggregatedRunnable(final Set<RequestListener<?>> listeners) {
        this.listeners = listeners;
    }

    @Override
    public void run() {

        if (listeners == null) {
            return;
        }

        Ln.v("Notifying " + listeners.size() + " listeners of request aggregated");
        synchronized (listeners) {
            for (final RequestListener<?> listener : listeners) {
                if (listener != null && listener instanceof MyPendingRequestListener) {
                    Ln.v("Notifying %s", listener.getClass().getSimpleName());
                    ((MyPendingRequestListener<?>) listener).onRequestAggregated();
                }
            }
        }
    }
}

扩展SpiceService并覆盖下面的方法（你将需要使用此定制的服务，而不是标准robospice服务）：

Extend SpiceService and override the following method (you will need to use this customized service instead of standard robospice service):

protected RequestListenerNotifier createRequestRequestListenerNotifier() {
    return new MyRequestListenerNotifier();
}

就是这样。现在，当你使用 addListenerIfPending ， onRequestAggregated（）时挂起的请求被发现就会被调用。

That's it. Now, when you use addListenerIfPending, onRequestAggregated() will be called when pending request IS found.

重要提示：这将只有当你在做请求时使用缓存的关键工作。例如，您可以使用空字符串（但不会 NULL）作为缓存键。

IMPORTANT NOTE: This will only work when you use Cache key when doing request. For example, you can use empty string (but NOT null) as cache key.

例如：

//doing request for the first time
spiceManager.execute(request, "", DurationInMillis.ALWAYS_EXPIRED, requestListener);
//...     
//checking if request is pending e.g. when activity is restarted
spiceManager.addListenerIfPending(responseClass, "", requestListener);

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